Re: reverse_iterator.hpp uploaded

From: Dietmar Kuehl (dietmar_kuehl_at_[hidden])
Date: 2000-06-12 17:37:59

Hi,

> From: <jsiek_at_[hidden]>
> > Oh, and on a separate note... there's an issue to be addressed with
> > std::iterator and the old g++ lib. I've noticed that in recent
> > revisions of boost/operators.hpp some #define's have been appearing
> > removing the iterator helpers that use std::iterator. How about
> > instead of removing the iterator helpers (which will break all of
> my
> > code that uses it) we provide std::iterator in boost. I know all
> the
> > reasons for not putting in std::iterator in boost, but again, its
> just
> > a workaround for a broken implementation.

My preferred solution to this is a different one, namely what I'm using
currently for my directory iterator rewrite:

  namespace boost
  {
  #if defined(__GNUG__) && !defined(_CXXRT_STD)
    template <class Category, class T,
      class Distance = BOOST_CSTD ptrdiff_t,
      class Pointer = T*, class Reference = T&>
    struct iterator
    {
      typedef T         value_type;
      typedef Distance  difference_type;
      typedef Pointer   pointer;
      typedef Reference reference;
      typedef Category  iterator_category;
    };
  #else
    template <class Category, class T,
      class Distance = BOOST_CSTD ptrdiff_t,
      class Pointer = T*, class Reference = T&>
      struct BOOST_DECL iterator:
  #  if defined(_MSC_VER)
      std::iterator<Category, T, Distance>
  #  else
      std::iterator<Category, T, Distance, Pointer, Reference>
  #  endif
      {
      };
  #endif
  }

The reason for this hack is that neither the library shipping with
gcc nor the library shipping with MSVC++ provide a usable version of
'std::iterator'. Thus, this code defines a 'boost::iterator' which does
something suitable... Of course, the if/defs need to be extended to
cover more compilers (my preferred solution to *this* problem would be
the use of autoconf but I think we were through this and rejected
autoconf mainly because most people didn't like it, if I remember
correctly...).

Regards,
  Dietmar

=====
<mailto:dietmar_kuehl_at_[hidden]>
<http://www.dietmar-kuehl.de/>

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